<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../../react18/react.development.js"></script>
    <script src="../../react18/react-dom.development.js"></script>
    <script src="../../react18/babel.min.js"></script>
</head>

<body>
    <div id="app"></div>
    <script type="text/babel">
        /* 
          props是用来做父子组件通信的
            - 在父组件中使用子组件的时候,可以给子组件添加属性
            - 在子组件中组件实例的props属性上,就能拿到这个属性和值
        
        */
        class Parent extends React.Component {
            state = {
                car: '大众'
            }
            render() {
                const { car } = this.state
                return (
                    <div>
                        <h1>我是父组件</h1>
                        <p>我开的车是{car}</p>
                        <button onClick={this.changeCarHandle}>change</button>
                       <Child car={car}/>
                    </div>
                )
            }
            changeCarHandle = () => {
                this.setState({
                    car: '奥迪RS7'
                })
            }
        }
        class Child extends React.Component{
            render(){
                let {car}=this.props
                car='天空蓝的'+car
                return (
                    <p>我是子组件我开{car}</p>
                )
            }
        }

        /* 
        当父组件更新状态的时候,子组件的render方法会重新执行生成新的虚拟DOM,也能拿到最新的props
      */

        const root = ReactDOM.createRoot(document.getElementById('app'));
        root.render(<Parent />)




    </script>
</body>

</html>